TM10-3930-660-34 16-4.  MAIN CONTROL VALVE ASSEMBLY - REPAIR This task covers: a. Removal c. Inspection e. Pre-Load Check of Bearing b. Disassembly d. Reassembly f. Installation INITIAL SETUP: Tools Tool Kit, Automotive Mechanics Shop Equipment, Automotive Maintenance, Common #2 Less Power Equipment Condition Boom cylinder flow control valve removed, TM10-3930-660-20. Main control valve assembly removed, TM10-3930-660-20. Materials/Parts Hydraulic Oil (App.  B, Item 35) Lint-Free Rags (App.  B, Item 38) O-rings (4, 9, 11, 14, 19, 23, 28, 30, 33, 38, 46, 55, 65, 66) DISASSEMBLY NOTE Do not remove relief valves unless they are being replaced. 1.  REMOVE AND DISASSEMBLE TWO MAIN RELIEF VALVES (1) IF NECESSARY. a. Remove nuts (2 and 3).  Remove and discard two seals (4) from nuts (2 and 3). b.   Remove adjusting screw (5), spring (6) and poppet (7). c. Remove  plug  (8),  O-ring  (9),  back-up  ring  (10)  and  O- ring (11). Discard O-rings (9 and 11). d. Remove  spring  (12),  piston  (13),  O-ring  (14),  back-up ring (15) and poppet (16 and 17).  Discard O-ring (14). 16-19